Method of heating carbon.



Patented June 21, 1910.

INVENTOR WITNESSES mam . treatment.

UNITED STATES PATENT oFFIoE.

I FRANK .1. TONE, or NIAGARA rAL'Ls, New YORK.

METHOD OF HEATING CARBON.

Heating Carbon, of which the following is a full, clear, and exact description, reference being had to the accom anying drawing, forming part of this speclfication, in which the figure is a sectionalside elevation showing one form of furnace for carrying out my invention. I p p My invention relates to the electric heating of carbon, for'the purpose of baking, purifying, polymerizing, graphitizing, or otherwise changing its character by heat Heretofore in carrying out this heat treatment, an electric furnace of the resistance type has been employed; and the resistance conductor has consisted either of the carbon material to be heated or of an independent carbon conductor, or of both used jointly. While fairly satisfactory reing the charge 3 of carbon to be treated.

4 and 5 are the upper and lower electrodes, which are shown as vertically disposed at the central part of the charge, the lower one projecting through the bottom of the receptacle. I have shown the u per electrode as surrounded by a shield 6 0 carbon or other refractory material, which may be suspended from the carbon holder 7 but is insulated therefrom by a refractory insulating layer 8.

When the electric current is supplied, an arc is established between the electrodes 4. and 5, and within the mass of carbon; and the heat thus generated is transmitted outwardly to the surrounding mass, thus baking, purifying, graphitizing, or giving the heat treatment desired. During this action, the shield for the upper electrode prevents contact between the charge and this electrode, and thus avoids shunting of the current around the are, which would give ordinary resistance heating of the carbon charge.

Specification 01 Letters Patent. Pate t d June Application filed February 4, 1907. Serial No. 355,745.

duction convection or radiation from the arc. An increase of efficiency is this Ohtalned over resistance heating, this being due to the greater amount of energy which can be generated, and supplied to a given volume of charge in a given time.' In a furnace of the'resistance type, a large'mass of charge is'heated in a single operation which must therefore extend over a comparatively long period of time. Radiation losses are di-' rectly proportional to the time of heating and are therefore large. The loss'of energy 3 in heating the mass of charge, outside of the effective heating zone, is large on account of the comparative slowness of energy production and supply. In the arc furnace, the productive heat energy constitutes a much larger proportion of the total energy because the reaction zone being smaller, the heating of a given mass can be accomplished in a much shorter period of time. For similar reasons, it is possible with are heating, to generate higher temperatures with the same electrical horse power, than with resistance heating, and this is of considerable importance in the production of graphite of certain grades. When carbon or graphite is heated to the intense heat of the electric are, not only are its physical characteristics changed, but any other substances such as silica, alumina, iron, calcium, etc., which may be commonlyassociated with it as im urities, are volatilized and driven out o the zone of high temperature. Such purification of carbon and graphite may be carried out in the arc process herein described, with great efficiency and economy.

I do not confine myself to the particular arrangement or number of electrodes shown.

in the drawing and many other arrangements may be used and will readily occur to those skilled in the art, which will accomplish the objects ofthe invention, it being essential that the charge of carbon does not come in contact with at least one of the electrodes and that the arc is operated within the mass of carbon treated. The method may be applied to the heating of any carbon articles and various carbonaceous materials; and the form of the furnace, electrodes, etc., may be varied widely without departing from my invention.

I claim 1. The method of heating carbon, consisting in forming an electric are within a charge composed of carbonaceous material,

thereby heating such material by transmission of heat from said arc; substantially as described.

2. The method of heating carbon, consisting in forming an electric arcbetween electrodes and within a charge composed of a mass of carbon, preventing any substantial contact between the carbon and one of the electrodes, and transmitting the heat of the arc into the carbon mass; substantially as described.

3. The method of olymerizing carbon, consisting in establishing an electric are within a charge composed of carbon, and substantially preventing the charge from contact with one of the electrodes, thereby heating the charge by transmitting the heat from the arc therein into such charge; substantially as described.

4. The process of graphitizing carbon, consisting in establishing an electric are within a mass of said carbon, and transmitting the heat of said are to the carbon to a suflicient amount to at least partially convert the same into graphite; substantially as described.

5. The method of purifying graphite, which consists in forming an electric are within a mass of impure graphite and between electrodes, preventing any "ubstantial contact between the carbon and one of the electrodes, and transmitting the heat of the arc to the graphite mass sufliciently to volatilize the impurities and allowing the volatilized products to escape from the graphite; substantially as described.

6. The method of heating carbon,vconsisting in embedding an electric are within a charge composed of a mass of carbon, and heating the carbon by transmission of heat therefrom; substantiall as described.

In testimony whereo I have hereunto set my hand.

' FRANK J. TONE. Witnesses:

JOHN MILLER, H. M. Coawm. 

